1. Field of the Invention
The present invention relates generally to releasable buckles which are conventionally positioned at at least one end of a strap or a web member and which may be conveniently secured together by interlocking such rigid buckles members, but conveniently released by manipulating the buckle member. More particularly the present invention relates to a releasable buckle structure and method in which an engaging member and a receiving member are interlocked with the receiving member including a U shaped portion having an open center adapted to receive a projection defined by a U shaped opening in the engaging member, both of the engaging member and receiving member being of a planar, curved configuration with the receiving member bearing upon the concave surface of the engaging member when in tension. Release is preferably accomplished by grasping and rotating the engaging member relative to the receiving member such that the receiving member rides along the curved surface, and ultimately exits at the slot defined at the bottom portion of the U shaped opening to release the buckle members.
2. Description of the Prior Art
Numerous releasable buckle structures are known. These buckles generally involve several important features, the most important of which are generally strength in tension, reliability of release when manipulated for that purpose, i.e., freedom from "hang-up", and convenience in interlocking the buckle members together. Among the simplist of such releaseable buckles is that illustrated in U.S. Pat. No. 1,142,842. While the "hooked end" releasable buckle illustrated is convenient to use and economic in structure, the open loop is subject to straightening under tension, and accordingly strength under tension is minimal.
U.S. Pat. Nos. 2,292,553 and 3,222,739 are illustrative of more complex releasable buckles which afford greater strength. For instance, as illustrated in FIGS. 4 through 8 of the first listed patent, an engaging member 21 is adapted to be received in slot 29, and when under tension, as illustrated in FIG. 8, provide a mutually reinforcing interface. While the patented releasable buckle is strong in tension and secure, as a result of the interlocking function of shoulder 28, disengagement is awkward in that the two buckle members must be rotated relative to one another with no convenient provision for such movement, and the members also must move laterally relative to one another for disengagement. This will generally require a positive, two handed operation which comprises convenience of release. The latter listed patent avoids this problem by providing a pivoting action when handle 34 is pulled, but again the device is subject to a hang-up in that T head 13 must move symmetrically into slot 12 upon release, or the undercut portion of T-head 13 may remain engaged on one side or the other of slot 12. Thus while the release action is convenient and operable with one hand, lateral shift of one member relative to the other during release can cause T-head 13 to hang-up in slot 12.